UNIVERSITY  OF  CALIFORNIA 

COLLEGE   OF   AGRICULTURE 

AGRICULTURAL    EXPERIMENT   STATION 

BERKELEY,  CALIFORNIA 


THE   TRACTOR 
ON   CALIFORNIA   FARMS 

L.  J.  FLETCHER  AND  C.  D.  KINSMAN 


BULLETIN  415 

December,  1926 


UNIVERSITY  OF  CALIFORNIA  PRINTING  OFFICE 

BERKELEY,  CALIFORNIA 

1926 


Digitized  by  the  Internet  Archive 

in  2012  with  funding  from 

University  of  California,  Davis  Libraries 


http://www.archive.org/details/tractoroncalifor415flet 


THE  TRACTOR  ON  CALIFORNIA  FARMS 

L.  J.  FLETCHEEi  and  C.  D.  KINSMAN2 


INTRODUCTION 

The  cost  of  power  and  labor  for  crop  production  in  California 
amounts  on  the  average  to  approximately  a  quarter  of  a  billion  dollars 
annually,  or  between  40  and  60  per  cent  of  the  total  cost.  Of  this 
amount,  approximately  one  hundred  and  five  million  dollars  is 
expended  for  power  and  one  hundred  and  forty-five  million  dollars 
for  labor.  This  means  an  average  annual  cost  for  these  items  of  about 
eighteen  hundred  dollars  per  farm,  or  twenty  dollars  per  acre  of 
improved  land.  For  this  reason,  the  farm  operator  is  very  much 
interested  in  utilizing  the  most  effective  labor  saving  devices  and  prac- 
tices available  and  in  selecting  that  type  and  size  of  power  equipment 
that  will  give  him  the  most  economical  results. 

The  gas  tractor  represents  at  the  present  time  the  principal  source 
of  power  for  field  work  in  California.  It  is  particularly  well  adapted 
for  the  types  of  farming  now  being  followed  and,  under  the  majority 
of  conditions,  it  has  been  found  to  be  the  most  economical  and  satis- 
factory field  power  available. 

Lack  of  sufficient  mechanical  knowledge  in  the  choice  of  tractors 
and  lack  of  skill  in  their  operation,  together  with  the  extremely  dry 
and  abrasive  nature  of  the  soil  encountered  in  some  parts  of  the 
State,  however,  have  made  their  successful  use  somewhat  difficult  on 
certain  farms. 

The  purpose  of  this  publication  is  to  aid  the  farmers  of  California 
in  the  choice  and  successful  operation  of  their  field  power  and  to 
impress  upon  manufacturers  and  dealers  the  need  of  supplying 
tractors  of  the  proper  design  and  type  to  meet  the  special  require- 
ments for  farming  in  California. 

The  information  contained  in  this  bulletin  is  based  on  data 
obtained  from  replies  to  questionnaires  mailed  in  1924,  to  all  known 
tractor  owners  in  the  State,  and  from  contact  with  tractor  owners  at 
short  courses  and  in  connection  with  other  extension  activities. 

Many  of  the  photographs  in  this  bulletin  illustrate  the  less  common 
uses  of  tractors.  In  general,  the  tractor  should  be  economically  em- 
ployed more  hours  per  year,  thus  reducing  the  cost  per  hour  by 
distributing  the  fixed  charges  over  a  longer  period  of  use. 

1  Associate  Professor  of  Agricultural  Engineering  and  Agricultural  Engineer 
in  the  Experiment  Station. 

2  Agricultural  Engineer,  Division  of  Agricultural  Engineering,  Bureau  of 
Public  Eoads,  United  States  Department  of  Agriculture. 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


CHOICE   OF    POWER 

Each  farm  is  an  individual  problem  when  the  power  requirement 
and  choice  of  equipment  are  being  considered  because  of : 

1.  Variation  in  the  managing  and  mechanical  skill  and  personal 

likes  and  dislikes  of  the  farm  operator. 

2.  Differences  in  type  of  farming  and  in  practices  followed  in 

caring  for  and  handling  the  individual  crops. 

3.  Size,  topography,  and  soil  conditions  of  the  farm. 

4.  Plans  for  future  developments. 

5.  Relative  cost  of  labor  and  of  the  various  kinds  of  available 

power. 

6.  Kind  and  availability  of  hired  power  and  possibility  of  doing 

custom  work. 

7.  The  ability  of  any  one  kind  of  power  to  do  all  of  the  neces- 

sary field  work. 

8.  Climatic  conditions,  such  as  high  temperatures  at  time  of  power 

application. 

9.  Available  capital. 

10.  Other  occupations,  if  any,  of  the  farm  operator. 
Since  each  kind  of  power  has  its  advantages  and  disadvantages,  each 
factor  should  be  weighed  in  proportion  to  its  relative  importance  as 
applied  to  the  particular  farm  in  question. 

The  personal  factor  is  a  very  important  item  in  the  choice  of 
power.  Some  farm  operators  are  mechanically  inclined  and  much 
prefer  tractor  poAver  if  the  other  factors  nearly  balance,  while  others 
have  a  personal  liking  for  animals  and  prefer  to  use  that  type  of 
power  under  the  same  circumstances. 

It  is  generally  conceded  that  for  some  operations  animal  power  is 
more  practicable  than  tractors;  while  for  others  tractors  are  the 
more  satisfactory.  Animal  power  is  frequently  better  adapted  for 
working  in  corners  and  other  cramped  or  difficult  places,  and  is 
much  more  flexible  than  tractor  power  because  of  the  ease  with  which 
the  size  and  combination  of  the  units  may  be  changed.  A  horse  or 
mule  also  has  a  great  overload  capacity,  that  is,  the  ability  to  exert, 
for  short  periods,  a  force  several  times  greater  than  that  normally 
exerted.  On  the  other  hand,  there  are  some  heavy  operations,  such 
as  subsoiling,  beet  lifting,  rice  field  checking,  and  deep  plowing  and 
cultivation,  where  animal  power  can  seldom  be  employed  satisfac- 
torily.    Fencing  demands  may  be  somewhat  less  when  tractor  power 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA    FARMS 


is  employed.  In  pulling  large  machines  such  as  combined  harvesters, 
the  tractor  takes  less  room  on  the  turns  and  can  get  in  closer  to 
the  fences,  thus  reducing  waste  land  around  the  fields.     Less  hired 


~^^*«i 


Fig.  1. — Planting  six  rows  of  beans  at  one  time  with  a  small  tractor  on  the 
Geo.  H.  Wilson  farm  near  Clarksburg.    A  six-row  cultivator  will  be  used  later. 


Fig.  2. — Rice  binders  are  mounted  in  front  of  tractors  and  are  used  to  open 
checks.  Considerable  rice  is  thus  saved  which  would  normally  be  tramped  down 
during  the  first  round.  The  binder  pictured  cuts  a  swath  directly  in  front  of  the 
tractor. 

help  also  is  necessary,  as  a  rule,  throughout  the  year.  Where  there 
is  sufficient  work  to  keep  the  entire  power  equipment  busy  the  greater 
part  of  the  year,  the  logical  arrangement  is  to  keep  both  tractors  and 
animal  power  and  to  use  each  where  it  is  most  efficient.     This  can 


b  UNIVERSITY    OF-  CALIFORNIA EXPERIMENT    STATION 

be  accomplished  without  much  difficulty  on  the  larger  farms  or 
ranches,  but  is  frequently  impracticable  on  the  smaller  ones. 

In  some  cases  and  particularly  on  the  smaller  fruit  ranches,  the 
farm  operator  devotes  only  a  part  of  his  time  to  his  farm  work, 
occasionally  being  engaged  in  some  other  occupation  during  the 
remainder  of  the  year.  In  such  cases,  the  tractor  has  an  advantage 
over  animal  power,  since  this  type  of  power  requires  no  care  or 
attention  while  idle. 

The  hiring  of  a  part  of  the  power  for  field  work  is  a  common 
practice  in  some  parts  of  the  State.     Some  farmers  keep  horses  and 


Fig.   3. — A   small  tractor   supporting  the   frame   and   operating   a   duster   for 
treating  grape  vines  with  calcium  cyanide  dust  in  the  Imperial  Valley. 

depend  on  hiring  tractors  to  do  a  part  or  all  of  their  heavy  work. 
Others  who  keep  one  or  more  tractors  and  no  animal  power,  depend 
upon  hiring  horses  to  do  the  light  work  that  cannot  be  done  con- 
veniently or  economically  with  the  tractor. 


Can  I  Make  Profitable  Use  of  a  Tractor  on  My  Farm? 

The  profit  derived  from  the  use  of  a  tractor  may  be  due  to  decreas- 
ing expense  of  farm  power  operation,  to  a  better  quality  of  work 
accomplished,  or  to  doing  some  seasonal  work  more  quickly  and  at 
more  nearly  the  proper  time  than  was  possible  with  methods  pre- 
viously employed. 

Many  successful  farmers,  before  considering  definitely  the  pur- 
chase of  any  certain  tractor,  have  carefully  listed  all  of  the  work 


BUL.  415]  the   TRACTOR   ON    CALIFORNIA   FARMS  7 

which  they  expect  it  to  do.  The  relative  cost  of  performing  this 
work  by  means  of  the  tractor,  as  compared  with  the  present  methods, 
is  next  determined  as  accurately  as  possible.  Owing  to  the  extensive 
use  of  tractors  in  California,  most  dealers  can  now  give  a  close  estimate 
of  the  amount  of  the  different  kinds  of  work  that  their  tractors  will 
do  per  hour  under  the  conditions  encountered  in  each  locality.  It  is 
advisable  also  for  prospective  purchasers  to  visit  other  farms  where 
tractors  are  used  and  gain  first-hand  information  concerning  the  size 
of  implements  operated  and  the  amount  of  work  done,  as  well  as  the 
general  satisfaction  given  by  the  tractor,  and  its  performance  after 


Fig.  4. — Kidger  and  tapper  used  by  Mr.  Paul  H.  Gray  in  his  citrus  grove  near 
Covina.    With  the  outfit  shown  above,  one  man  can  ridge  and  tap  ten  acres  a  day. 

a  few  years'  use.  Sometimes  it  is  well  to  discount  somewhat  the 
owner's  statements  of  what  he  can  accomplish  with  his  tractor, 
although  as  a  rule  reliable  information  can  be  obtained  after  an 
explanation  of  the  purpose  of  the  inquiry.  However,  it  is  well  to 
keep  in  mind  the  fact  that  the  size  of  the  tractor  must  be  determined 
to  a  large  extent  by  its  ability  to  handle  satisfactorily  the  heaviest 
load  that  will  be  assigned  to  it  during  the  year. 

After  a  certain  tractor  is  tentatively  decided  upon,  it  is  well  to 
determine  next  the  approximate  number  of  hours  that  it  will  be  used 
annually  in  doing  the  work  on  the  farm.  In  many  cases,  the  sound- 
ness of  the  investment  depends  very  much  upon  the  amount  of  time 
the  tractor  is  to  be  used. 


8 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Data  secured  from  questionnaires  and  other  sources  indicate  that 
the  average  tractor  in  California  is  operated  about  650  hours  per  year. 
However,  many  of  the  more  successful  farmers  keep  their  tractors 
busy  from  1000  to  2000  hours  per  year,  thus  materially  reducing  the 
cost  of  operation  per  hour. 

Studies  made  of  tractors  in  use  in  the  State  indicate  that  the 
owner's  estimate  of  the  life  of  a  tractor  in  years  is,  to  a  large  extent, 
independent  of  the  amount  it  is  used  per  year.  When  a  tractor  is 
used  only  300  or  400  hours  per  year,  the  fixed  charges  such  as  interest, 
depreciation,  and  repairs  due  to  age,  housing,  and  taxes,  amount  to 


. 


5. — A  tractor  pulling  a  rice  binder.  Note  that  the  binder  mechanism  is  being 
operated  by  means  of  a  power  take-off  from  the  tractor  engine.  This  is  one  of 
the  more  recent  tractor  developments  which  is  now  being  adapted  to  the  operation 
of  combines  as  well  as  of  binders.  This  system  of  drive  will  undoubtedly  be 
extended  to  many  other  farm  machines  whose  mechanism  is  now  operated  by 
ground  driven  wheels. 

more  than  the  operating  costs ;  while  tractors  used  for  from  1000  to 
1500  hours  per  year  show  fixed  charges  amounting  to  somewhat  less 
than  one-half  of  the  operating  cost. 

There  are  occasions  also  when  the  tractor's  ability  to  do  a  large 
amount  of  work  in  a  short  time  is  the  deciding  factor  in  its  favor. 
This  applies  particularly  to  tillage  in  the  spring  or  after  rains  or 
irrigation,  as  well  as  in  some  harvesting  operations.  Where  sheep 
are  allowed  to  graze  in  the  field  during  the  winter  months,  longer 
feeding  periods  are  secured  because  of  the  fact  that  spring  plowing 
may  be  delayed. 

The  tractor  is  every  year  finding  new  ways  of  serving  on  the 
farm  more  efficiently.     Belt  power  is  taken  from  the  tractor  to  drive 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA    FARMS 


more  stationary  farm  machines,  while  many  new  attachments  are 
proving  labor  savers. 

The  power  take-off  is  being  rapidly  adapted  to  many  farm  tools. 
This  device  consists  of  a  flexible  extension  shaft  fitted  with  suitable 
couplings,  universals,  and  sliding  joints  for  transmitting  power  from 
the  tractor  engine  directly  to  the  mechanism  of  field  machines  as 
they  are  pulled  by  the  tractor.  When  such  machines  as  binders  and 
potato  diggers  are  driven  through  a  power  take-off,  their  operation 
is  much  steadier  and  the  total  power  requirements  are  less  than  when 


Fig.  6. — A  recent  tractor  development.  This  machine  not  only  plows  and 
operates  other  common  tillage  tools,  but  is  also  adapted  to  such  practices  as 
cultivating  row  crops  and  mowing.  The  mower  shown  above  is  operated  by  a 
power  take-off.  Practically  all  machines  used  with  this  tractor  are  designed  for 
one  man  control. 

they  are  driven  through  a  ground  wheel.  The  use  of  this  power  take- 
off on  such  machines  as  spray  pumping  outfits  also  saves  the  cost  of 
a  portable  engine. 

A  modified  type  of  tractor  with  high  clearance  has  recently  been 
developed  to  cultivate  row  crops  in  addition  to  performing  the  usual 
operations. 

Each  year  sees  the  development  of  new  and  more  efficient  farm 
tools  especially  built  for  use  with  tractors,  and  implement  manu- 
facturers are  finding  it  necessary  to  change  from  the  making  of 
animal  drawn  tools  to  special  tractor  tools  in  order  to  meet  the 
demand. 


10  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


What  Should  I  Consider  in  Buying  a  Tractor? 

If  a  careful  survey  of  all  conditions  indicates  that  a  tractor  is 
likely  to  be  a  profitable  investment,  the  next  question  is  the  make 
and  type  to  buy.  The  more  important  factors  influencing  the  make 
of  the  tractor  purchased  are : 

1.  The  cost  of  power  during  the  life  of  the  tractor,  based  upon 

initial  cost,  operating  expense,  repairs,  and  probable  life. 

2.  The   design   and  construction   of  the  tractor  itself,   including 

quality  of  materials,   workmanship,   accessibility,   and  dust 
exclusion. 


Fig.  7.— Dust  is  the  principal  enemy  of  the  tractor  in  California.  This  scene 
is  quite  typical  of  tractors  operating  tillage  machinery  on  loose,  dry  soils  where 
an  efficient  air  cleaner  is  essential  for  low  operating  cost.  If  used  without  air 
cleaners,  tractor  motors  may  wear  out  in  a  few  days  of  operation.  Other  parts  of 
the  machine,  sucli  as  wheel  and  track  bearings,  should  also  be  designed  to  exclude 
dust. 

3.  General  suitability  of  the  tractor  to  the  kind  of  work  to  be  done. 

4.  The  general  satisfaction  given  by  the  tractor  after  working,  for 

a   considerable   period,   under   similar   conditions   on   other 
farms. 

5.  Nearness  of  a  dependable  dealer  who  keeps  a  good  stock  of 

repair  parts. 

6.  Stability  and  business  reputation  of  the  manufacturer. 
Protection  of  the  tractor's  mechanism  from  dust  is  an  important 

consideration  under  all  field  conditions,  particularly  where  the  soil 
is  of  an  especially  abrasive  nature.  An  efficient  air  cleaner  is  the 
first  essential  in  protecting  a  tractor  from  dust,  and  regardless  of  the 
type,  should  not  require  attention  more  often  than  once  a  day.     The 


BUL.  415]  THE   TRACTOR   ON    CALIFORNIA   FARMS  11 

location  of  the  air  intake  has  been  found  to  have  an  important  bearing 
on  the  amount  of  dust  encountered.  Wherever  possible,  a  "peri- 
scope" should  be  placed  on  the  air  intake  so  that  the  supply  will 
be  drawn  in  above  or  in  front  of  the  tractor  where  the  air  is  relatively 
free  of  dust.  On  most  tractors,  the  crank  case  breather  should  also 
be  equipped  with  a  cleaner,  and  special  means  should  also  be  provided 
to  prevent  dust  from  entering  the  wheel  bearings,  starting  mechanism, 
magneto  drive-shaft  bearings,  and  housings  of  all  moving  parts. 

Means  for  proper  and   convenient  lubrication  of   all  parts   are 
essential.     However,  there  is  a  marked  tendency  in  tractor  design 


Fig.  8. — A  tractor  pulling  a  plane  on  sandy  soil.     The  long  spade  lugs 
used  on  the  tractor  have  proved  very  efficient  on  loose  soils. 

toward  the  reduction  of  the  number  of  lubricating  places  requiring 
frequent  attention  from  the  operator.  The  tractor  motor  should  be 
provided  with  a  positive  devise  for  distributing  oil  to  all  wearing 
surfaces.  An  oil  pressure  gauge  is  desirable,  to  give  a  check  on  the 
pump  operation,  as  well  as  an  indication  of  the  relative  viscosity  of 
the  oil,  and  means  should  be  provided  for  easily  draining  the  crank 
case  of  all  used  oil.  Oil  niters  and  cleaners,  which  remove  such  con- 
tamination as  dust  and  dilution  from  excess  fuel,  will  reduce  the 
engine  wear  considerably.  These  devices  are  now  being  perfected  and 
will  be  available  for  attachment  to  the  tractor  engine. 

One  of  the  most  important  matters  in  the  selection  of  wheel 
tractors  is  the  proper  lug  equipment  so  as  to  insure  satisfactory 
traction.  This  especially  applies  to  farms  having  sandy  or  very  light 
soils.     Owing  to  the  fact  that  many  tractors  are  now  manufactured 


12  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

for  a  world  market  and  may  be  equipped  with  a  wide  variety  of 
tractive  devices,  it  is  important  that  proper  types  be  secured.  In 
most  parts  of  California,  a  fairly  long  spade  lug  has  proved  most 
efficient  on  wheel  machines.  Track  type  tractors  need  no  additional 
lugs  or  special  tracks  except  on  marshy  land  or  very  soft  soil.  Many 
operators  do  not  realize  the  loss  due  to  wheel  slippage.  If  this  is 
due  to  overloading,  the  tool  may  be  narrowed  in  many  cases  and  the 
load  thus  lightened.  Whenever  a  tractor  wheel  slips,  the  effect  on 
the  tractor  as  far  as  fuel  and  oil  consumption  and  wear  are  concerned 
is  practically  the  same  as  though  the  tractor  had  pulled  the  load  an 
additional  distance  equal  to  the  slippage.  Positive  steering  control 
on  both  wheel  and  track  type  tractors  is  very  essential  in  orchard  or 
vineyard  work.  High  bands  on  front  wheels,  proper  weight  distribu- 
tion, and  properly  designed  swinging  drawbars  aid  considerably  in 
steering.  Tractors  with  individual  drives  or  clutches  for  the  wheels 
or  tracks  can  usually  be  turned  shorter  and  are  more  positive  of 
control. 

In  this  type  of  machine,  however,  it  is  essential  that  the  steering 
clutches  be  of  ample  capacity  and  that  they  operate  without  slipping 
or  grabbing.  It  is  also  necessary  that,  when  turning,  one  driver  be 
able  to  pull  the  load. 

"What  are  the  relative  advantages  of  track  and  wheel  tractors?" 
This  is  a  question  frequently  asked  by  the  prospective  tractor  buyer. 
The  opinions  of  about  500  of  the  owners  who  answered  the  question- 
naire are  reflected  by  their  replies  to  the  question,  "Which  type  of 
drive  do  you  prefer — wheel  or  track?"  The  farmers  who  preferred 
wheel  tractors  listed  the  following  reasons,  which  are  given  in  the 
order  of  frequency: 

First  cost  lower. 

Wheels  less  complicated  than  tracks. 

Expense  of  up-keep  less  on  the  wheel  tractor. 

Riding  easier  on  rough  ground  for  the  operator. 
Those  preferring  the  track  type  give  as  their  reasons: 

Better  traction  on  loose  soils. 

No  packing  of  the  soil. 

Quicker  and  shorter  turning. 

Less  damage  to  road  surfaces. 

It  is  quite  evident  from  these  replies  that  many  of  the  owners  had 

had  experience  with  only  the  one  type  of  tractor,  that  is,  wheel  or 

track.     Recent  developments  in  tractor  design  and  construction  are 

tending  to  improve  the  tractive  ability  of  wheel  machines  by  the 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA   FARMS 


13 


Fig.  9. — Tractors  for  orchard  operation  should  have  all  projecting  parts  cov- 
ered, thus  avoiding  damage  to  trees.  High  bands  on  the  front  wheels  and  a 
swinging  drawbar  aid  in  steering.  Note  also  the  scrapers  provided  for  cleaning 
the  space  between  the  spade  lugs.  This  is  one  of  the  most  effective  methods  of 
keeping  the  gr outers  clean  and  thus  aiding  traction. 


Fig.  10. — Tractors  may  often  be  efficiently  employed  to  pull  a  series  of  tools. 
On  the  tractor  illustrated  above,  notice  how  the  swinging  drawbar  aids  the  tractor 
in  turning  while  pulling  the  heavy  orchard  disc  harrow  and  clod  masher.  Note 
also  the  electric  lights  provided  on  the  tractor  for  night  operation.  During  cer- 
tain times  of  the  year  a  very  large  amount  of  work  may  be  obtained  from  a 
tractor  by  operating  day  and  night  without  increasing  the  farm  investment  for 
equipment. 


14 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


use  of  better  types  of  lugs,  and  steering  is  made  more  positive  by 
the  use  of  better  designed  swinging  drawbars  and  high  bands  on  the 
front  wheels.  The  life  of  the  tracks  on  track  machines  is  being 
materially  lengthened  by  the  use  of  more  wear-resisting  materials,  by 
re-designing  the  track  bearings  to  eliminate  dust  more  effectively  and 
by  general  improvements  resulting  from  observation  of  types  of  track 
construction  which  have  given  trouble  on  previous  models. 

A  tractor  should  be  equipped  with  an  ignition  system  well  enclosed 
against  dust  and  provided  with  a  rugged  enclosed  impulse  starter 
coupling  or  other  means  of  making  starting  easy  under  such  adverse 


Fig.  11. — Because  of  its  mobility  and  power,  the  tractor  is  the  most  common 
type  of  drive  used  for  operating  ensilage  cutters.  A  good  governor  for  the 
tractor  engine  is  required  for  dependable  and  efficient  operation. 


conditions  as  cold  weather  or  stiffness  from  recent  overhauling.  The 
radiator  should  also  be  of  rugged  design  and  so  made  that  the  core 
may  be  removed  and  easily  cleaned. 

Accessibility  for  the  adjustment  of  parts,  lubrication,  and  repair- 
ing are  items  which  should  be  given  careful  attention  by  the  pros- 
pective buyer.  The  parts  which  usually  receive  the  most  frequent 
attention  are  spark  plugs,  carbureter,  moving  parts  of  the  ignition 
system,  valve  tappets,  crank-shaft  bearings,  and  fan  belts.  Fan  belts 
should  be  eliminated  wherever  possible  in  the  design.  Provisions  for 
efficient  servicing  of  the  tractor  are  important.  This  refers  to  large 
and  easily  manipulated  openings  in  fuel  tanks,  radiator  drains,  air 
cleaners,  and  places  receiving  oil  or  grease. 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA    FARMS 


15 


For  most  classes  of  work  an  engine  governor  is  very  desirable. 
It  prevents  the  racing  of  the  engine ;  makes  field  operation  easier ;  in 
stationary  work  insures  a  constant  speed,  which  is  often  essential; 
and  also  provides  protection  from  the  racing  of  both  the  engine  and 
belt-driven  machine. 


Fig.  12. — Subsoiling  30  inches  deep  with  a  tractor  in  a  foothill  citrus  grove. 
The  ability  to  operate  implements  on  steep  grades  is  one  of  the  requirements  of 
tractors  for  foothill  orchard  work. 


0 


Fig.  13. — Cultivating  twelve  rows  of  beans  at  one  time  on  the  Sutter  Basin 
Company  farm.  Note  that  extension  axles  are  used  to  place  the  driving  tracks 
between  the  roAvs.  In  order  that  the  cultivator  may  register  with  the  rows,  the 
common  practice  is  to  plant  at  one  operation  as  many  rows  as  are  to  be  cultivated. 

It  is  well  to  consider  the  comfort  of  the  operator.  This  relates 
particularly  to  the  ease  of  steering,  convenience  of  the  control  levers, 
sunshades,  foot  rests,  location  of  the  exhaust  outlet,  direction  of  fan 
discharge,  which  should  not  be  toward  the  operator,  and  the  use  of 
fenders  to  protect  the  driver  and  guard  him  from  dust.     The  line 


16  UNIVERSITY    OP    CALIFORNIA EXPERIMENT    STATION 

of  vision  should  not  be  blocked  by  engine  or  radiator,  and  last  but 
not  least,  a  comfortable  and  properly  located  seat  should  be  provided. 
There  is  usually  a  more  or  less  direct  relationship  between  the 
weight  of  a  modern  tractor  and  the  amount  of  draft  that  can  be 
exerted  at  the  drawbar.  Most  of  the  modern  tractors  exert  a  pull 
equal  to  from  60  to  80  per  cent  of  their  weight.  In  other  words,  a 
tractor  weighing  5000  pounds  can  usually  exert  a  pull  on  the  draw- 
bar of  from  3000  to  4000  pounds.  As  a  rule,  however,  a  tractor 
operating  in  loose  soil  should  not  be  expected  to  pull  in  excess  of 
60  per  cent  of  its  weight  and  still  steer  well  and  not  suffer  from 
slipping  of  the  drivers. 


What  are  the  Most  Important  Factors  Influencing  the  Cost  of 
Operating  a  Tractor  f 

With  very  few  exceptions  the  success  of  a  tractor  seems  to  be 
largely  independent  of  the  make,  working  conditions,  or  implements 
used,  its  success  being  influenced,  rather,  by  (1)  the  ability  of  the 
farm  operator  to  utilize  the  tractor  to  the  best  advantage,  and  (2) 
the  character  of  the  mechanical  attention  given  the  tractor. 

Many  prospective  tractor  OAvners,  when  discussing  costs  of  oper- 
ation, seem  to  be  concerned  chiefly  with  the  fuel  and  oil  costs.  The 
replies  to  questionnaires  sent  to  California  tractor  owners  indicate 
that  fuel  and  oil  constitute  on  the  average  only  about  one-half  of 
the  total  operating  costs,  the  other  operating  costs  being  made  up 
largely  of  interest,  depreciation,  and  repairs.  Some  of  the  more 
successful  operators,  however,  have  found  that  these  last  items  con- 
stitute only  about  one-third  of  the  total  expense.  A  number  of  the 
latter  were  questioned  as  to  what  they  considered  the  most  essential 
factor  in  the  efficient  utilization  of  a  tractor.  The  following  are 
typical  answers: 

"Do  not  overload  the  tractor,  but  at  the  same  time  see  that  it  is 
pulling  the  proper  load.  Avoid  racing  the  engine  and  starting  loads 
with  jerks.     This  invariably  causes  rapid  wear  and  breakage." 

' '  Plan  the  work  so  that  tractors  will  run  as  many  hours  as  possible, 
and  at  the  same  time  see  that  each  tractor  is  made  to  pull  the  proper 
load  and  is  doing  the  proper  kind  of  work.  The  use  of  tools  especially 
built  for  the  work  being  done  will  increase  the  efficiency  of  the  tractor 
and  reduce  the  cost  of  doing  the  work." 

"Keep  the  tractor  clean.  We  have  a  special  rack  and  wash  our 
tractors  every  night.     We  are  certain  this  keeps  a  large  amount  of 


BUL.  415]  THE    TRACTOR    ON    CALIFORNIA    FARMS  17 

dust  from  working  into  the  bearings,  and  it  gives  us  a  chance  to 
inspect  our  tractors  completely  every  day." 

' '  Have  but  one  man  operate  and  care  for  the  tractor.  This  insures 
more  careful  attention  to  lubrication  and  adjustment  and  permits  the 
placing  of  responsibility,  which  it  is  difficult  to  do  when  more  than 
one  man  operates  the  machine." 

Where  a  number  of  tractors  are  operated  in  a  group  or  fleet,  as 
on  the  larger  farming  enterprises,  experience  has  shown  that  the  best 
results  are  obtained  by  employing  men  who  are  familiar  with  farming 
operations  to  drive  the  tractors,  entrusting  to  one  or  more  well  trained 
mechanics  all  mechanical  care  from  minor  adjustments  to  complete 
overhauling. 

Occasionally  tractors  are  used  to  operate  implements  intended  for 
either  larger  or  smaller  tractors  or  animal  power  units.  This  often 
results  in  overloading,  with  its  attendant  rapid  wear  or  breaking  of 
parts,  or  underloading  and  high  cost  per  acre  per  unit  of  work  accom- 
plished. Tractor  owners  may  reduce  the  cost  of  operation  materially 
by  using  combinations  of  implements,  especially  where  one  implement 
alone  will  not  make  a  sufficient  load.  By  carefully  planning  the 
work  of  the  tractor  in  advance,  one  man  saves  much  time  which  is 
otherwise  lost  in  making  extra  trips  to  the  machine  shed  for  other 
implements  or  in  traveling  considerable  distances  between  fields.  A 
tractor  service  wagon  in  which  fuel,  oil,  and  grease,  and  certain  spare 
parts  are  kept  will  prove  a  good  investment. 

There  is,  however,  little  doubt  concerning  the  importance  of  the 
operator  in  keeping  down  repair  costs  and  loss  of  time.  Regular  and 
conscientious  attention  to  such  matters  as  lubrication  and  cleaning, 
and  a  knowledge  of  farm  practices  are  qualifications  as  important 
as  mechanical  skill.  There  are,  moreover,  sections  of  California  where 
severe  dust  conditions  are  encountered.  Wear  is  more  rapid  in  such 
sections,  although  proper  design  and  construction  of  the  tractor  and 
careful  maintenance  tend  to  decrease  the  wear. 

That  attention  to  mechanical  details  is  important  is  evidenced  by 
the  following  suggestions  from  successful  tractor  owners: 

1 '  Keep  the  fuel  and  oil  cans  clean ;  drain  the  crank  case  often,  the 
frequency  depending  upon  the  dustiness  of  the  work." 

"  Watch  the  air  cleaner.  This  is  the  most  important  part  of  the 
tractor  as  far  as  keeping  down  engine  wear  is  concerned.  See  that 
it  is  functioning  properly;  time  spent  in  caring  for  the  cleaner  is 
well  invested." 


18  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

"Watch  the  adjustment  of  the  carbureter;  keep  the  fuel  mixture 
as  lean  as  possible  without  heating  the  engine  and  causing  lack  of 
power.  This  will,  to  a  large  extent,  prevent  oil  dilution  and  the 
forming  of  carbon." 

"Keep  all  bearings  in  proper  adjustment.  Do  not  wait  for  crank- 
shaft bearings  to  pound  and  wheel  bearings  to  get  so  loose  that  they 
interfere  with  operation." 

Practically  all  of  the  1800  tractor  owners  who  answered  the 
questionnaire  gave  definite  information  concerning  certain  features 
of  tractor  design.  Owners  were  practically  unanimous  in  mentioning 
the  desirability  of  inspection  plates  on  the  engine,  the  value  of  engine 
governors,  and  adjustable  drawbars;  83  per  cent  desired  a  service 
brake,  and  90  per  cent  a  clutch  brake ;  50  per  cent  preferred  three 
forward  speeds,  45  per  cent  two,  and  only  5  per  cent  were  satisfied 
with  one  speed.  That  easy  starting  is  favored  was  evidenced  by  the 
fact  that  98  per  cent  of  those  answering  the  questionnaire  desired  an 
impulse  starter  coupling  on  the  magneto.  Less  than  one-half  of  the 
replies  indicated  a  desire  that  the  tractor  be  suitable  for  row  crop 
cultivation.  Fourteen  per  cent  stated  that  their  service  manuals  were 
not  satisfactory,  some  having  received  no  manual  at  all.  The  main 
reasons  given  were  that  the  books  were : 

1.  Too  technical,  not  being  clear  enough  for  average  operator. 

2.  Written  to  cover  older  models  and  made  no  reference  to  new 

parts. 

3.  Lacking  in  detail  and  did  not  explain  how  to  get  at  and  repair 

inaccessible  parts. 

4.  Without  lubrication  chart,  there  being  oiling  places  mentioned 

which  could  not  be  found  on  the  tractor. 

It  is  the  manufacturer's  duty  to  furnish  each  owner  with  a  book 
containing  complete  instructions  for  operation,  care,  and  repair  of 
his  tractor;  in  turn,  the  operator  should  study  the  book  carefully 
and  thus  become  thoroughly  familiar  with  his  machine.  There  are 
instances  where  unusual  wear  has  resulted  from  the  operator's  over- 
looking some  important  place  requiring  lubrication  or  allowing  some 
parts  to  get  out  of  adjustment  even  when  the  manual  of  operation 
sent  with  the  tractor  contained  complete  instructions  as  to  lubrication 
and  adjustment. 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA    FARMS 


19 


Fig.  14. — The  stationary  gas  engine  furnishes  7  per  cent  of  all  power  used  on 
the  farms  in  California.  In  many  places  these  engines  serve  to  eliminate  a  large 
amount  of  hand  labor,  thus  materially  reducing  the  cost  of  production  or  handling 
of  farm  products. 


I 


Fig.  13. — A  small  tractor  adapted  for  cultivation  of  onions, 
wheel  axle  extensions  and  spade  lugs. 


Note  the  drive 


20 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


ANALYSIS  OF   FARM   POWER  COSTS 

The  total  amount  of  primary  power  used  on  farms  in  California 
amounts  to  approximately  two  million  horsepower,  and  the  horse- 
power hours  developed  annually  by  this  power  are  over  one  billion. 
Though  the  cost  of  this  power  varies  considerably,  according  to  the 
kind  and  quantity  being  used,  the  average  is  just  about  nine  cents  per 
horsepower-hour  and  the  total  cost  for  all  kinds  used  amounts  then 
to  approximately  one  hundred  million  dollars  per  year.3 


TABLE  1 

Approximate  Amount  and  Cost  of  Power  Used  on  Farms  in  California 


' 

Number 

of 

units 

Average 
primary 

H.P. 
per 

unit 

Total 
primary 
horse- 
power 

Average 

H.P. 

hours  per 

primary 

H.  P.  per 

year 

H.  P.  hours  per 
year* 

Cost 
per 
H.P. 
hour, 
cents] 

Total 

annual 

cost 

Type  of  power 

Total 

Per 
cent 

(in 
mil- 
lions) 

Horses  and  mules.. 

Electric  motors 

Tractors 

Stationary  engines.. 
Windmills 

305,500 
35,000 
35,000 
30,000 
26,000 
25,000 

1 
14 
13t 

6 

V* 

20 

305,500 
490,000 
455,000 
180,000 
13,000 
500,000 

650 
1,130 
600  § 
450 
800 
100 

198,575,000 
553,700,000 
273,000,000 
81,000,000 
10,400,000 
50,000,000 

17 

47.5 

23 

7 

1 

4.5 

23 
3 

10|| 

6 

5 
20 

45.7 
16.6 
27.3 
4.9 
.5 
10.0 

Totals 

1,943,500 

600 

1,166,675,000 

9 

105.0 

*  Tractors  and  animals  furnish  practically  all  the  power  used  directly  for  field  work.  About  95  per 
cent  of  the  power  developed  by  tractors  and  75  per  cent  of  the  animal  power  are  used  for  this  purpose. 

t  The  cost  figures  given  include  fixed  and  operating  charges  but  not  operator's  time.  Wages  for  the 
operator  were  excluded  in  these  computations  because  they  vary  indirectly  with  the  size  of  unit  used, 
and  also  because  in  many  operations  much  of  the  time  of  tne  operator  is  devoted  to  manipulation  of 
the  machinery  used  rather  than  caring  for  the  power  unit. 

%  Drawbar  rating. 

§  Includes  belt  work,  which  is  a  small  percentage  of  the  total. 

||  Cost  per  drawbar  horsepower-hour.    Belt  power  is  approximately  half  of  the  amount  shown. 


3  Power  is  the  term  used  for  indicating  the  rate  of  developing  energy  or  of 
doing  work,  and  is  usually  measured  in  foot  pounds.  One  horsepower  represents 
the  power  equivalent  to  performing  work  at  the  rate  of  33,000  foot  pounds 
per  minute.  For  example,  a  horse  walking  two  and  a  half  miles  per  hour  or 
220  feet  per  minute  and  exerting  a  pull  of  150  pounds  on  the  singletree  would 
be  developing  power  at  the  rate  of  one  horsepower  (220  X  150 1=  33,000  foot 
pounds).  A  tractor  traveling  three  miles  per  hour  or  264  feet  per  minute  and 
exerting  a  pull  of  1500  pounds  on  the  drawbar  would  be  developing  12  horse- 
power (264X1500  =  396,000  foot  pounds.  And  396,000-^33,000  =  12  horse- 
power). An  ordinary  farm  horse  will  be  developing  power  at  the  rate  of  approxi- 
mately one  horsepower  while  doing  heavy  plowing  or  disking.  A  horsepower-hour 
is  equal  to  33,000  X  60  =  1,980,000  foot  pounds  and  is  the  common  unit  used  for 
measuring  quantity  of  work  done.  An  ordinary  farm  horse  will  develop,  on  the 
average,  approximately  five  horsepower-hours  of  work  during  a  ten-hour  work  day. 

The  term  "horse  hour"  is  used  frequently  in  farm  accounts  and  should  not 
be  confused  with  the  term  horsepower  hour.  A  "horse  hour"  is  the  time  of  one 
horse  for  one  hour  and  has  no  connection  with  the  amount  of  work  done  during 
the  hour. 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA    FARMS 


21 


Table  1  shows  the  approximate  amount  and  cost  of  each  principal 
kind  of  power  used  on  farms  in  California.  It  will  be  seen  from  this 
table  that  animal  power  furnishes  about  17  per  cent  of  the  total 
power,  electric  motors,  47  per  cent,  tractors,  23  per  cent,  stationary 
engines  7  per  cent,  windmills  1  per  cent,  and  motor  trucks  5  per  cent. 


Fig.  16. — Tractor  cultivating  five  rows  of  cotton  with  cultivators  originally 
designed  for  two  rows  each.  Note  center  extension  shovels  so  that  a  fifth  row  is 
included.     Two  men  cultivate  60  acres  per  day. 


.-".-- 1 


Fig.  17. — Plowing  and  operating  combined  harvesters  on  large  grain  ranches 
were  two  of  the  first  uses  for  tractors  in  California.  Smaller  combines  with 
auxiliary  engines  are  now  being  used,  the  tractor  serving  only  to  pull  the  machine. 


22  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Of  the  kinds  of  power  shown,  horses,  mules,  and  tractors  are  those 
used  primarily  for  field  work.  About  75  per  cent  of  the  animal 
power  and  95  per  cent  of  the  tractor  power  developed  are  being  used 
for  this  purpose.  Electric  motors  represent  the  largest  quantity  of 
any  kind  of  power  used  on  farms  in  California,  but  its  use  consists 
almost  entirely  of  stationary  work  such  as  pumping  for  irrigation 
and  drainage.  A  small  amount  of  stationary  engine  power  is  utilized 
for  field  work  by  means  of  cable  outfits.  This  application,  however, 
is  confined  almost  entirely  to  preparing  the  ground  for  sugar  beet 
production  and  the  cultivation  and  harvesting  of  this  crop. 


Cost  of  Field  Power 

The  cost  of  using  any  kind  of  power  is  made  up  of  two  major 
items,  namely,  fixed  costs  and  direct  operating  costs.  The  fixed  costs 
are  those  items  which  occur  independently  of  the  amount  the  power 
unit  is  used;  the  direct  operating  costs  are  those  that  vary  with 
the  amount  of  power  that  is  developed. 

In  the  case  of  tractor  power,  the  fixed  charges  consist  of  interest 
on  investment,  housing,  taxes,  insurance,  and  depreciation,  repairs 
and  replacements  due  directly  to  obsolescence  or  non-use;  and  the 
direct  operating  costs  include  such  items  as  fuel,  lubricating  oil, 
grease,  wages  of  the  operator,  and  depreciation,  repairs  and  replace- 
ments due  directly  to  wear.  If  animal  power  is  being  considered,  the 
fixed  charges  include  interest  on  investment,  housing,  taxes,  insurance, 
the  value  of  feed  consumed,  and  care  required  when  not  used  for  work, 
and  the  depreciation  due  directly  to  aging ;  while  the  direct  operating 
costs  consist  of  the  extra  feed  and  care  required,  operator's  wages, 
and  the  extra  depreciation  that  will  take  place  wThile  the  animal  is 
being  worked. 

Since  the  fixed  costs  must  be  prorated  against  the  power  actually 
developed  in  order  to  determine  the  cost  per  unit  of  power  utilized, 
the  number  of  hours  the  power  equipment  is  u§ed  annually  has  a 
very  decided  bearing  upon  the  total  cost  per  horsepower-hour.  If 
the  power  equipment  is  used  only  a  few  hours  each  year,  the  fixed 
costs  represent  the  larger  part  of  the  cost  of  the  power ;  while  if  the 
annual  use  is  large,  the  fixed  charges  become  small  compared  with 
the  direct  operating  costs.  Table  2  shows  the  approximate  cost  per 
horsepower-hour  and  the  annual  cost  per  rated  drawbar  horsepower 
of  using  tractors  in  California  under  1926  conditions,  wages  for  the 
operator  not  being  included.    Table  3  shows  similar  figures  for  animal 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA    FARMS 


23 


power.  The  data  for  cost  of  tractor  operation  is  based  upon  replies 
obtained  from  about  500  tractor  owners,  practically  all  prominent 
makes  of  tractors  being  represented,  while  the  animal  power  costs 
are  based  on  data  from  various  farm  management  and  other  cost- 
production  studies.  Figure  18  shows  graphically  the  data  contained 
in  tables  2  and  3. 

TABLE  2 
Approximate  Cost  of  Tractor  Power  in  California  under  1926  Conditions* 
Average    annual   fixed    cost    of   keeping    a   tractor    per   rated    drawbar 

horsepower  $21.00f 

Average  direct  operating  costs  per  drawbar  housepower-hour  developed 
by  tractor: 

Fuel,  lubricating  oil  and  labor  for  servicing  tractor $.04 

Depreciation  and  repairs  due  directly  to  use 02 

Total  $.06 

Total  fixed  and  direct  operating  costs  per  drawbar  horsepower-hour  and  per 
year  for  different  amounts  tractor  is  used  annually: 


Power  developed 
annually  per  rated 
drawbar  horse- 
power of  tractor 

Fixed  costs  per 

horse-power-hour 

of  power 

developed 

Direct  operating 
costs  per  horse- 
power-hour of 

power  developed 

Total  costs  per 

horsepower-hour 

of  power 

developed* 

Total  annual  cost 

per  drawbar 

horsepower  of 

tractor 

H .  P.  hours 

Cents 

Cents 

Cents 

Dollars 

0 

$21.00 

100 

21.0 

6.0 

27.0 

27.00 

200 

10.5 

6.0 

16.5 

33.00 

300 

7.0 

6.0 

13.0 

39.00 

400 

5.3 

6  0 

11.3 

45.20 

500 

4.2 

6.0 

10.2 

51.00 

600 

3.5 

6.0 

9.5 

56.00 

800 

2.6 

6.0 

8.6 

68.80 

1000 

2.1 

6.0 

8.1 

81.00 

1200 

1.8 

6.0 

7.8 

93.60 

1500 

1.4 

6.0 

7.4 

111.00 

2000 

1.1 

6.0 

7.1 

142.00 

2500 

0.8 

6.0 

6.8 

170.00 

*  Wages  of  operator  while  in  field  not  included. 

t  The  fixed  costs  include  interest,  taxes,  insurance,  and  housing  computed  at  10  per  cent  on  an 
average  investment  of  $57.00,  and  depreciation  and  repairs  due  to  age,  at  14  per  cent  on  an  average  first 
cost  of  $105.00  per  rated  drawbar  horsepower  of  the  tractor. 

It  should  be  noted  that  in  the  case  of  tractors  and  animals  the 
cost  figures  shown  are  only  for  a  single  drawbar  horsepower.  The 
approximate  cost  of  operating  any  certain  size  of  power  unit  may 
be  obtained  by  multiplying  the  costs  given  by  the  rated  drawbar 
power  of  the  tractor  or  by  the  number  of  animals  in  the  size  of  team 
being  used  and  adding  to  this  the  wages  paid  or  allowed  for  the 
operator. 

For  example,  if  we  take  a  tractor  of  ten  drawbar  horsepower  used 
an  average  of  500  hours  annually,  and  an  operator  who  is  paid  or 


24 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


TABLE  3 
Approximate  Cost  of  Animal  Power  in  California  under  1926  Conditions* 

Average  annual  fixed  costs  of  keeping  each  work  animal $92.00f 

Average  direct  operating  cost  per  horsepower-hour  developed  by  each 

work  animal   .09 

Total  average  fixed  and  direct  operating  costs  per  horsepower-hour  and  per 
year  for  different  amounts  of  time  work  animals  are  used  annually: 


Power  developed 
annually  per 
work  animal 

Fixed  costs  per 

horsepower-hour 

of  power 

developed 

Direct  operating 
costs  per  horse- 
power-hour of 
power  developed! 

Total  costs  per 

horsepower-hour 

of  power 

developed 

Total  annual  cost 
per  work  animal 

H.  P.  hours 

Cents 

Cents 

Cents 

Dollars 

0 

$92.00 

100 

92 

9.0 

101 

101.00 

200 

46 

9.0 

55 

110  00 

300 

31 

9.0 

40 

120  00 

400 

23 

9.0 

32 

128.00 

500 

18 

9.0 

27 

135.00 

600 

15 

9.0 

24 

144.00 

800 

11 

9.0 

20 

160.00 

1000 

9 

9.0 

18 

180.00 

1200 

8 

9.0 

17 

204.00 

1500 

6 

9.0 

15 

225.00 

2000 

5 

9.0 

14 

280.00 

*  Wages  of  driver  not  included. 

t  The  fixed  costs  include  cost  of  feed  and  care  while  idle,  shelter,  interest,  taxes,  insurance,  equip- 
ment and  depreciation  due  to  age.     (See  California  Agricultural  Experiment  Station  Bulletin  401.) 

t  Direct  operating  costs  include  additional  feed  and  care  required  while  in  use  and  increased  depre- 
ciation and  mortality  due  to  use. 


1000  1500  2000 

Horsepower-Hours   Developed  Annually 

Fig.  18. — Approximate  operating  cost  of  horse  and  tractor  power  for  different 
amounts  of  work  performed  annually. 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA    FARMS 


25 


allowed  50  cents  an  hour  or  $250  for  operating  the  tractor  during 
the  season,  then  the  approximate  cost  of  operation  per  hour  and  per 
year  may  be  obtained  as  follows:  From  table  2  or  figure  18,  w^find 
that  the  average  cost  for  using  a  tractor  500  hours  annually  is  10.2 


Fig.  19. — Land  leveling  is  one  of  the  common  tractor  operations  in  California. 
Small  levelers  are  made  for  one  man  operation  and  are  placed  either  behind  or 
in  front  of  the  tractor. 


Fig.  20. — A  tractor  performing  an  operation  formerly  requiring  three  trips 
of  a  team  and  man  through  the  vineyard.  The  sharp-edged  bands  on  the  wheels 
cut  the  sucker  vines,  a  float  levels  the  soil  between  the  vine  rows,  and  a  scraper 
forms  a  ridge  along  one  side.  Later,  trays  containing  the  drying  raisins  are 
placed  with  one  edge  on  the  ridge,  thus  allowing  more  rapid  drying. 


26  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

cents  per  horsepower  hour,  or  $51.00  per  year  per  drawbar  horse- 
power. Then,  the  total  cost  of  operating  a  ten-horsepower  tractor 
under  these  conditions  will  be  ten  times  $51.00  plus  $250,  or  $760 
per  year.  If,  on  the  other  hand,  the  tractor  is  used  1000  hours 
annually,  we  find  from  table  2  or  figure  18  that  the  cost  will  be  8.1 
cents  per  horsepower-hour  or  $81.00  per  drawbar  horsepower.  Ten 
times  $81.00  plus  50  cents  times  1000  for  the  operator  gives  a  total 
cost  of  $1310  per  year.  Computations  for  animal  power  may  be 
obtained  in  a  similar  way  by  using  the  data  from  table  3  or  figure  18. 
It  will  be  noticed  from  these  examples  and  from  the  tables  that 
as  the  number  of  hours  the  power  unit  is  used  annually  increases,  the 
cost  per  hour  of  operation  decreases. 


Depreciation  and  Upkeep  of  Field  Power 

Depreciation  of  either  tractors  or  animal  power  is  due  to  two 
principal  factors,  namely,  aging  or  obsolescence,  and  wear  and  tear, 
when  in  use. 

The  useful  life  of  the  average  farm  work  animal  is  probably 
about  ten  years,  and  the  average  amount  such  an  animal  is  used 
annually  in  California  is  about  1300  hours,  during  which  time  it 
develops  an  average  of  one-half  horsepower-hour  of  power  per  hour, 
or  650  horsepower-hours  of  power  per  year.  If  the  animal  were 
worked  continuously  for  eight  or  ten  hours  per  day  during  each  day 
of  the  year,  it  would  probably  develop  at  least  2000  horsepower 
hours  of  power  during  the  year,  but  it  would  be  practically  worn  out 
and  useless  at  the  end  of  three  or  four  years  of  such  service.  On 
the  other  hand,  if  it  were  worked  only  a  few  hours  a  year  or  not 
at  all,  its  period  of  usefulness  would  probably  not  exceed  twenty  or 
twenty-five  years.  This  means  that  a  depreciation  of  4  or  5  per  cent 
of  the  maximum  value  of  the  work  animal  should  be  included  under 
the  item  of  fixed  charges  and  that  sufficient  additional  amounts  should 
be  included  under  the  item  of  fixed  charges  and  operating  charges  to 
take  care  of  the  depreciation  due  to  use. 

In  the  case  of  tractor  power,  a  determination  of  the  depreciation 
charges  is  much  more  complicated  than  with  animal  power  because 
of  the  variation  in  the  design  of  the  tractor  and  the  quality  of 
materials  entering  into  the  construction  of  the  different  designs  and 
makes  of  tractors,  the  radically  different  conditions  under  which 
tractors   are   required   to   work,    and   the   great    difference    in   the 


Bul.  415] 


THE   TRACTOR   ON    CALIFORNIA   FARMS 


27 


mechanical  skill  of  the  operator  and  his  conscientiousness  in  caring 
for  his  machine. 

In  the  reports  obtained,  465  tractor  owners  gave  their  estimate 
of  the  life  of  their  machines,  together  with  information  as  to  the 
amount  they  were  being  used  annually.  The  amount  the  tractors  were 
used  varied  from  less  than  a  hundred  to  more  than  twenty-five  hun- 
dred hours  per  year  and  the  estimated  life  from  three  years  to  more 
than  thirty. 

Grouping  the  reports  according  to  the  number  of  hours  the 
tractors  were  used  annually  and  averaging  the  estimates  of  the  length 
of  life  of  the  tractors  in  each  group  give  some  idea  of  the  relation 
existing  between  these  two  factors.  The  results  of  this  grouping  is 
shown  in  table  4  and  figure  21. 

TABLE  4 
Estimated   Life   of   Tractor   as    Influenced   by   Annual   Use* 


Number  of  hours 
used  per  year 

Number  of 
reports 

Average  age 

at  time  of 

reporting, 

years 

Estimated 
life, 
years 

Hours  used 
in  1923 

Estimated  life 

in  hours  of 

use 

200  and  less 

61 

3.49 

8.72 

154 

1,346 

201-  400 

149 

3.23 

8.09 

312 

2,524 

401-  600 

112 

3.39 

7.83 

497 

3,894 

601-  800 

53 

3.17 

7.49 

695 

5,207 

801-1000 

36 

3.57 

6.96 

920 

6,402 

1001-1400 

37 

2  80 

7.54 

1160 

8,745 

1401-1800 

12 

2.66 

6.38 

1525 

9,728 

1801-2200 

2 

2.75 

6.50 

2075 

13,488 

2201-2600 

3 

3.19 

5.66 

2441 

13,814 

3.27 

7.84 

547 

4,287 

*  This  table  is  based  on  data  from  465  of  the  1800  answered  questionnaires  received.    Only  the 
questionnaires  which  were  completely  filled  out  were  used  in  this  computation. 


It  will  be  seen  from  this  table  that  while  the  average  amount  the 
tractors  in  each  group  were  used  varies  from  154  hours  to  2441  hours 
a  year,  the  average  estimated  life  only  varies  from  8.72  years  to  5.66 
years,  and  that  the  average  tractor  becomes  obsolete  after  about  nine 
years,  even  if  it  is  not  used  at  all.  This  means  that  an  amount  equal 
to  about  11  per  cent  of  the  first  cost  of  the  tractor  should  be  included 
under  fixed  charges  to  cover  obsolescence  and  that  a  sufficient  addi- 
tional amount  should  be  included  under  the  operating  charges  to  take 
care  of  the  direct  wear. 


28 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


15,000 


^10,000 


■-55,000 


0  y 

0 

< 

/ 

Z 

±s 

/  ° 

0 

/o 

-7 

.- 

a. 

< 

LV 

/  \ 

e^ 

0 

0 

L 

£E    IT 

±  Y^ 

^RS 

0 

■    ^e 

0 

/ 

/ 

/ 
/ 
/ 

t 

1000 

Hours  Used  Annually 


2000 


Fig.    21. — Kelation   between   the   hours    tractors    are    used   annually    and 
average  total  life  in  years  and  hours  of  use. 


the 


DETERMINING   SIZE   OF  TRACTOR 

The  size  of  tractor  best  suited  for  any  certain  farm  depends  partly 
upon  the  amount  of  work  to  be  done  and  partly  upon  the  nature 
of  the  operations  to  be  performed. 

It  is  shown  under  the  discussion  of  cost  of  operation  that  the 
more  a  tractor  is  used  annually,  the  cheaper  will  be  the  cost  per 
hour  of  use.  Since  it  usually  requires  more  time  to  accomplish  a 
given  piece  of  work  with  a  small  tractor,  such  a  tractor  would  prob- 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA    FARMS 


29 


ably  be  used  a  greater  number  of  hours  in  a  year,  resulting  in  a 
lower  cost  per  unit  of  work  done  than  when  a  larger  tractor  is  used. 
This  rule  will  not  hold  true  in  every  case,  however,  because  the  wages 
of  the  operator  are  usually  greater  per  unit  of  work  accomplished 
with  a  small  power  outfit  than  with  a  large  one.  Up  to  a  certain 
point,  therefore,  as  the  size  of  power  unit  employed  is  increased,  the 
cost  per  unit  of  work  done  is  decreased  because  of  a  saving  in  oper- 
ator's wages.  Beyond  this  point,  however,  the  extra  cost  of  operating 
the  tractor  more  than  offsets  the  saving  in  wages.     This  is  illustrated 


1250  1000  833     667 


Total    Hours  Tractor  is  Used    per  Year 
500  400  333  286  250 


222 


200 


1500 


1000 


500 


8      10     12 


20  25  30  35  40 

Size   of  Tractor  -  Drawbar  Horsepower 


Fig.  22.— Comparative  cost  of  doing  10,000  horsepower  hours  of  field  work  per 
year  with  tractors  of  various  sizes. 


in  figure  22  for  a  specific  case  of  10,000  horsepower-hours  of  work  to 
be  performed  with  a  tractor  annually.  In  this  particular  case,  the 
most  economical  size  of  tractor  would  be  about  15  drawbar  horse- 
power. It  should  be  noted,  however,  that  if  more  or  less  work  per 
year  were  to  be  done,  that  if  a  considerable  part  of  the  work  were  such 
that  a  15  horsepower  tractor  could  not  be  used  efficiently,  or  if  the 
wages  of  the  operator  were  different,  the  most  economical  size  of 
tractor  would  also  probably  be  somewhat  different. 

There  are  two  other  factors  which  also  may  have  an  important 
bearing  on  the  size  of  power  unit :  In  the  production  of  most  crops, 
there  are  some  operations  that  affect  the  crop  yield  materially  if  they 
are  not  done  at  the  proper  time.     In  such  cases,  it  is  possible  that 


30 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


a  larger  outfit  than  the  most  economical  one  would  prove  more  profit- 
able because  of  the  possibility  of  its  doing  the  work  faster.  In  other 
cases,  there  are  such  necessary  operations,  as  subsoiling,  which  may 
require  a  greater  minimum  amount  of  power  than  is  the  most 
economical  for  the  remainder  of  the  work.  Usually  under  such  con- 
ditions, not  economy  but  operations  to  be  performed  control,  to  a 
considerable  extent,  the  size  of  power  unit  to  be  selected.  Other 
factors  influencing  the  size  of  the  tractor  to  be  purchased  are :  amount 


Fig.  23. — A  five-standard  subsoiler  operating  on  a  farm  of  the  California 
Packing  Corporation.  Subsoilers  and  deep  tilling  cultivators  are  used  extensively 
on  California  farms.  Owing  to  their  deep  penetration  draft  requirements  are 
high  and  they  are  operated  almost  altogether  by  tractors. 


of  custom  work,  if  any,  to  be  done ;  the  value  of  that  part  of  the 
operator's  time  not  devoted  to  the  driving  of  the  tractor;  possibility 
of  hiring  other  power ;  belt  uses,  such  as  operating  a  pump  or  ensilage 
cutter;  and  the  number  of  horses  replaced  or  disposed  of. 

There  is  sometimes  a  tendency  to  purchase  too  light  or  too  small 
a  tractor,  because  the  work  of  the  machine  is  based  upon  the  existing 
practices  rather  than  upon  the  probable  developments  in  the  use  of 
heavier  machinery  and  deeper  tillage,  which  frequently  follow  the 
purchase  of  a  tractor. 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA    FARMS 


31 


Fig.  24. — A  large  tractor  pulling  a  "V"  crowder  which  is  constructing  in  one 
operation  a  levee  for  rice  growing.  The  speed  with  which  levees  may  be  built  by 
this  method  is  a  great  advantage. 


Fig.  25. — Steam  cable  outfit  pulling  a  six-row  beet  lifter  on  a  ranch  near 
Spreckels,  California.  This  outfit  consists  of  two  large  steam  tractors,  one 
placed  at  each  side  of  the  field.  The  implement  is  pulled  across  the  field  by 
cables  connected  to  drums  on  the  tractors. 


32  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


RESPONSIBILITY    FOR    THE    SUCCESS    OF    THE    TRACTOR 

The  manufacturer,  dealer,  and  owner  all  have  a  responsibility  in 
the  success  of  the  tractor. 


Responsibility  of  the  Manufacturer 

The  manufacturer,  in  the  design  of  his  tractor,  should  consider 
the  incorporation  of  proved  features  which  will  lower  the  operating 
costs,  such  as 

1.  Accessibility  of  parts  for  lubricating,  adjusting,  and  replacing. 

2.  The  reduction  of  wear  by  better  dust  protection,  and  the  use 

of  wear-resisting  materials. 

3.  The  reduction  of  the  cost  of  parts  most  frequently  replaced 

because  of  wear. 

4.  The  introduction  of  devices  for  better  economy  in  the  use  of 

fuel  and  oil. 

The  comfort  and  safety  of  the  operator  should  be  considered. 
An  easy  starting  system  for  the  engine  is  highly  desirable.  In  keep- 
ing with  the  price,  all  materials  and  such  accessory  parts  as  magnetos, 
carbureters,  and  spark  plugs  of  high  quality  should  be  provided, 
together  with  accurate  workmanship  to  allow  ease  in  the  replacing 
of  repair  parts. 

Manufacturers,  as  far  as  it  is  practicable  to  do  so,  should  adapt 
their  tractors  to  meet  successfully  special  conditions  which  are 
encountered  in  the  production  of  certain  crops. 

A  complete,  well-illustrated  service  manual  and  list  of  repair  parts 
should  be  furnished  with  each  tractor.  The  manufacturer  should 
select  dealers  carefully  and  insure  good  repair  stocks  and  service. 

Responsibility  of  the  Dealer 

The  dealer  should  know  the  farm  conditions  in  his  territory  so 
that  he  can  advise  the  farmer  accurately  as  to  the  suitability  of  his 
tractor  for  various  types  of  soils  and  crops.  He  should  also  keep  on 
hand  all  repair  parts  likely  to  be  needed  by  the  owner  and  should 
establish  means  of  obtaining,  without  delay,  other  parts  from  the 
manufacturer.  Competent,  courteous  service  men  should  be  employed, 
and  each  new  owner  should  be  given  complete  directions  and  instruc- 
tions as  to  the  care  and  operation  of  his  tractor. 


BUL.  415]  THE   TRACTOR   ON    CALIFORNIA   FARMS  -33 


Responsibility  of  the  Owner 

The  owner  also  has  a  certain  responsibility.  He  should  not  use 
a  new  tractor  for  his  heaviest  work  but  should  break  it  in  gradually, 
just  as  he  would  care  for  a  new  automobile.  At  no  time  should  a 
tractor  be  overloaded,  overspeeded,  or  jerked.  Care  should  be  taken 
to  provide  ample  lubrication,  and  the  working  parts  should  be  in- 
spected at  intervals  and  adjusted,  if  necessary.  All  owners  should 
become  familiar  with  the  instruction  book  and  attempt  to  carry  out 
the  directions  of  the  manufacturer. 


TRACTOR    COST   RECORDS 

The  real  value  of  keeping  records  of  tractor  operating  costs  and 
performance  is  emphasized  by  the  following  excerpt  from  a  report 
by  a  tractor  expert  after  he  had  visited  a  number  of  farms  in  Cali- 
fornia : 

"I  was  especially  impressed  with  the  fact  that  in  successful  tractor 
operation  a  competent  operator  and  good  bookkeeping  were  factors 
of  equal  or  greater  importance  than  any  other  two  factors  entering 
into  the  situation.  Almost  without  exception  where  the  tractor  was 
in  the  hands  of  a  good  operator  and  careful  records  of  its  performance 
were  being  kept,  the  owner  was  well  satisfied  with  the  work  of  the 
machine." 

Many  starting  to  keep  records  on  a  tractor  make  the  mistake  of 
trying  to  use  a  very  complicated  system.  A  few  suggestions  for  keep- 
ing a  tractor  record  follow: 

1.  Plan  a  system  simple  and  easy  to  keep. 

2.  Enter  daily  an  account  of  hours  of  work,  kind  and  amount  of 

work  done. 

3.  Record  the  amount  and  cost  of  supplies  used  by  the  tractor, 

such  as  fuel,  oil,  and  grease,  as  well  as  repair  parts,  labor, 
and  repairing.  If  these  items  are  purchased  separately, 
entries  may  be  made  when  the  supplies  or  repair  bills  are 
received  or  when  payments  are  made.  If  fuel  and  oil,  how- 
ever, are  drawn  from  a  common  storage,  some  convenient 
system  should  be  provided  for  indicating  their  use.  Taxes 
should  be  included  on  this  record. 


34 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


4.  Record  the  total  time  of  operator  in  driving,  servicing,  or  repair- 

ing the  tractor,  including  the  amount  of  wages  plus  the  value 
of  board,  lodging,  or  other  perquisites. 

5.  Enter  for  later  reference  first  cost  of  tractor  and  tools  or  extras 

purchased  for  use  in  repairing  or  operating  of  tractors. 


Fig.  26. — On  larger  ranches,  factory  production  methods  may  be  used  to 
advantage.  Above  is  a  reproduction  of  a  typical  daily  chart  taken  from  one  of 
the  tractors  used  on  the  James  Mills  Orchard  Company  ranch  near  Hamilton  City. 
A  mechanic  is  placed  in  charge  of  all  tractors  on  this  ranch.  A  certain  amount  is 
agreed  upon  at  the  beginning  of  the  year  as  a  reasonable  hourly  cost  for  each 
tractor.  The  mechanic  then  receives  a  bonus  at  the  end  of  the  year  if  the  operat- 
ing cost  is  less  than  that  previously  agreed  upon.  Operators  are  paid  on  the  time 
clock  basis,  and  when  their  tractor  is  in  the  shop  for  repairs  they  draw  only  the 
current  day  laborer's  wage.  This  system  provides  an  incentive  to  keep  their 
machines  in  good  repair  and  operating  in  the  field,  thus  securing  a  very  low  cost 
per  hour  for  tractor  operation. 


Bul.  415] 


THE    TRACTOR    ON    CALIFORNIA    FARMS 


35 


The  following  is  a  convenient  form  for  a  tractor  record: 
Tractor  Work  Eecord 


Month 


Day 


Hours  worked 


Kind  of  work 


Amount 


Remarks 


If  a  common  fuel  supply  is  used  for  tractor,  truck,  and  automobile, 
list  fuel  for  tractor  on  a  separate  card.  Where  the  tractor  is  filled 
with  fuel  daily,  the  entire  work  and  field  record  may  be  kept  on  a 
card  placed  in  some  convenient  location  near  the  fuel  tank. 

Tractor  Cost  Eecord  . 

1.  Make  of  tractor Model Serial  No 

Engine  No 

2.  Cost  of  tractor Cost  of  tools  or  extras  purchased  for  use  in 

repairing  or  operating  a  tractor 

3.  Taxes  on  tractor 

4.  Supplies,  repairs,  etc.,  used  by  tractor: 


Month 

Day 

Item  (such  as  fuel,  oil, 
grease  or  repairs) 

Bill  number 

Cost 

Remarks 

Fig.  27. — Making  nine  irrigation  furrows  in  one  operation  in  an  orange  grove. 

15w-12,'26 


